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Re: [PATCH] teach emit_store_flag to use clz/ctz


On 05/03/2012 08:23 AM, Paolo Bonzini wrote:
Yeah, not as I posted...  of course config/mips/mips.h needs change, but
do you disagree that all targets_do_  have the same value at zero for
the optab as they have for RTL?

I don't agree without a port-by-port review, no.


If, as you suggest, we get proper agreement between the gimple-level
(aka optab level) definedness and the rtl-level definedness, then we
should drop the tri-state and go back to simple boolean.

I'm uncertain if there's any point in settings such as for rs6000,
where we do know that ctz(0) = -1.  Should we only define the value
for clz(0) = wordsize and let the rtl optimizers fold ctz(0) away?



r~


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